Naruto's birthday (October 10), was Health and Sports Day in Japan when his character was conceived. The holiday, however, was later moved to the second Monday of October in 1999.
Sasori shares the same birthday (November 8) as the creator and author of Naruto, Masashi Kishimoto. Additionally, his birth date makes Sasori's Western astrological sign Scorpio, and his name (蠍) means "scorpion".
Rock Lee shares the same birthday as Bruce Lee (November 27).